1. Field of the Invention
The present invention relates to a hardware device controller, an image forming apparatus, and a control method.
2. Description of the Related Art
Conventionally, when an abnormality occurs in a CPU of an information processing apparatus and a motor driving apparatus having a plurality of controlling units, the data and apparatuses are protected by forcibly stopping the control signals and the supply of power. Configurations having a watchdog timer have been used widely to detect such an abnormality in the CPU, and by causing the watchdog timer to monitor a clear signal transmitted from the CPU, the power supply is cut off when an abnormality occurs in the CPU. In this manner, a configuration that enhances the protectiveness of a device by causing a watchdog timer to monitor a runaway of software in a CPU has been known.
Japanese Patent Application Laid-open No. 2011-56852, for example, discloses a technology in which a watchdog timer monitors an abnormality in a hardware device controlled by a CPU, and when an abnormality occurs, stops a load such as a motor.
However, in the conventional technologies as described above, when an abnormality occurs in a relay unit such as an I/O expander connected to a controlling unit (CPU), an abnormality in a hardware device cannot be monitored accurately. Accordingly, the hardware device cannot be stopped accurately at the time of the occurrence of abnormality.
Therefore, there is a need to accurately monitor an abnormality in a relay unit such as an I/O expander connected to a controlling unit (CPU) and to accurately stop a hardware device in the case of the occurrence of abnormality.